Extra large CDMA antenna

A 7 foot high antenna is a _big_ antenna to put on a vehicle. A number of amateur radio operators run antennas this size but especially during 4WDing there is a significant chance of breaking something.

Look at the dB (decibel) gain figure for each antenna this is a partial measure of it's efficiency - an increase of 3dB equates to a doubling of the signal which _does not_ equate to a doubling of the distance you can operate over. In real conditions an extra 3dB may make little difference - otoh it may mean you can _just_ make a call when otherwise you would not be able too. I guess "you pays your money and takes your chance"? Personally I wouldn't pay $220 for a CDMA antenna or want a 7 foot pole hanging off the vehicle.

Mike Harding

I went to WACB. On his recommendation I bought a 6bd antenna, he reckoned it is 40 times better that phone antenna. It’s about 800mm long, cost was about $170. Mounted it on a SS bracket ($37) from ARB.

I picked up a 6db with spring base (about 1m or so) from Dicksmith of all places, $130.
Works really well and it's not even located very well height wise as it's mounted to the low nudge bar on the surf. We very rarley drop out while out bush, only in really hilly terrain when your down the bottom or if we really go out of the way. On most highways we have coverage all the time.

Im in the process now of removing a 2.1m aerial we have strapped to the side of a donger for CDMA fax/phone comms. I first started with a 900mm Scalar 6db and that barely held the signal, the 2.1m was no significant increase. I have had to go to a directional aerial now (painful.)
If someone does find something out of sight for CDMA, do share. Also, does anyone know what the rule is for determining the length of the wire to add on to the aerial base? Im keen to see if I can do anything to help the signal im getting.

Have a look at Mobile One Tri-band CN8918S, 5db, 1100mm, and has a locking grub screw on the base.

Hi V8Diesel,

I too have the Nokia 6225 with full car kit and RFI 1795 antenae (approx 800mm long). On my UHF, I run a 2.1m aerial when out of town and have noticed a significant improvement in range. My UHF experience has shown the taller the antenae, the better the range (and noticeably better, not just a minor improvement).

But to translate that to CDMA experience is not straightforward. Due to their nature, CDMA has a finite distance (approx 100kms from a base station), unlike UHF. So while the bigger CDMA antenae cannot extend the range greater than 100kms, within the 100 km boundary it will give better chance of reception depending on terrain. This is purely due to the extra height to get your signal higher up. You would be just as well off putting a standard CDMA antenae on an extension pole!!!

Personally, I would stick with the RFI 1795 for the CDMA, but I do like my 2.1m UHF when out of town (gotta watch those tree covered tracks though!).

Cheers

Captain

PS. Currently in London at the moment, haven't seen a single car phone antenae here at all, range does not seem to be a problem! Everyone seems to run bluetooth ear pieces here.